1. Field of the Invention
This invention relates to a semiconductor memory device which is highly integrated.
2. Description of the Prior Art
An integrated semiconductor memory device has been known from, for example, U.S. Pat. No. 3,387,286. The memory cell is composed of diffused layers formed in a substrate, an isolation oxide which isolates differents elements from each other, as well as a gate oxide film formed in contact therewith, an electrode for forming a storage capacitance as made of polycrystalline silicon, a gate similarly made of polycrystalline silicon, an insulating film covering the electrode and the gate, and a metal electrode serving as a word line. Among these components, the gate electrode, the gate oxide film and the diffused layers constitute a switching transistor, while the storage capacitance forming electrode, the gate oxide film and a part of the diffused layer constitute the storage capacitance. The switching transistor and the storage capacitance are two-dimensionally so arranged on one plane that they don't overlap each other. The prior art accordingly has the disadvantage that the area of the memory cell becomes large.